Method for preventing the formation of frost crystals in the circulating lines of refrigerating machines



RCULATING I amoemtoz 72m .lymw/ JET/2W H. J. SMITH ION OF FROST CRYSTALS IN THE CI June '26, 1923.

METHOD FOR PREVENTING THE FORMAT LINES OF REFRIGERATING MACHINES Filed June 8 Patente dune 26, 1923;,

,'reu sra'ras P T E NT METHOD FOR PREVENTING TEE FORMATION OF FROST CRYSTALS IN THE CIRCULAT- ING LINES F REFRIGERATING MACHINES,

To all whom it may concern: Be it known that HAZOR JUDsoN SMITH, a citizen of the United States residing at Springfield, in the county of I-iampden and State of Massachusetts, has invented certain new and usefullmprovements in Methods for Preventing the Formation of Frost firystals in the Circulating Lines of Refrigerating Machines, of which the following is 0 a specification, reference being made to the accompanying drawing, forming a part thereof, 7 I

This invention relates to refrigerating cycles in a refrigeration machine more particularly to the private dwelling type, in which ethyl chloride, methyl chloride or liquid refrigerant of similar properties are used; In machines of this character using the refrigerants enumerated serious operatingdifiiculties have been encountered due to the formation of frost crystals prevailing through the circulating lines of the low side of the a paratus. These frost crystals are formed rom Water in the system which may 5 come from condensation in the lines, moisture intlie oiling and sealing medium and moisture in the refrigerating agent itself.

In the use of ethyl chloride, methyl chlo- 3 ride or similar agents, it has been found that these frost crystals will accumulate more particularlyat the expansion valve, but also at any point in the circulating lines, such as at the bend or elbow or some low spot in 5 the lines. At such points the frost crystals hecoine solidly massed and shut off the cir- J culation of the refrigerant, thereby causing the machine to cease functioning, so far as refrigerating is concerned. It becomes 'necessary under such circumstances to stop the machine and allow this frozen water to thaw, then the machine can again be started and refrigeration will continue. however, that the desired and particularly low temperatures cannot be obtained because this freezing-up condition is; accumulated from any point below 32 degrees Fahrenheit in the low or expansion side.

The objects of this invention 'is to provide a liquid refrigerant and circulate it'in the lines in such a manner that this difficulty is entirely overcome and the formation of these frost crystals is prevented within the work-1 ing temperature of the machine.

I in the lines.

It is found,

Application filed an a, 1922. Serial No. teaseo.

The reason that ethyl chloride has not W been used successfully before seems to be because of the operative diliiculties of keepmg the gas dry or free from water and has proved a very decisive factor in driving experlmenters to the other agents, such as sulphur dioxide, ln machines pulling a. high operative vacuum, any water in the lines will freeze at the primary expansion point and clog the lines. The harder the machine pulls the harder the freeze-up. There are two reasons for this-one, the evaporation of the ethyl chloride and the other, the evaporation under high vacuum of part of the water itself, Sublimation from he surface of the frozen water constantly furnishes .small amounts of water to the high side which flows into the liquid receiver alon with the liquefied gas. This fundamenta factor of sublimation prevents fixing the water in any one spot by freezing for it will ultimately land at the expansion valve in spite of all precautions.

l have found a cure for this freezing which consists in putting an alcoholic sludge in the lines that is sufficient in quantity to prevent freezing, even at the lowest temperature, of any amount of water that could possibly be 7 I find that denatured alcohol is very good. The alcohol constantly travels through the lines of the low side and mixes with the water therein. This mixture of water and alcohol can pass the expansio valve without having any efi'ect upon the valves or lines; Three or four ounces is sufficient for the largest domestic unit.

lhave discovered that h the addition of alcohol to the circulating ines of a refriigcrating apparatus in which ethyl chlori e, methyl chloride or similar refrigerants are employed, the alcohol would dissolve ordeliquesce'the frost crystals as rapidly as they form, and that the alcohol and moisture, or water,- would together form a non-freezing sludge, which can slowly travel through the low side to some pocket without obstructin Ill the line, which can also freely pass throug the expansion valve without obstructin it; I have further discovered that t tenancy of this sludge is to rest quiescent in some low point in the circulating lines, suchas' in the low oint of a in the circulating coils or in 510 low side 0 a hollow cylinder or drum. d

ice.

Due to the fact that the refrigerants ethyl chloride, methyl chloride or similar agents are so much more volatile than alcohol, and that they will boil at a much lower tem perature, these refrigerants will circulate freely in the lines, boil off their gas, and leave behind a more sluggishly moving mass of alcohol and water. The addition of alcohol to the refrigerant in the circulating system of a refrigerating apparatus successfully isolates all traces of moisture or water, permits the free circulation of the refrigerating agent, and therefore, successful functioning of the machine under all conditions of practical operation, and enables the refrigerant to produce any desired temperature of which 'the' refrigerant to the particular cycle illusa paratus illustrating my invention and i 2 shows a variation of the expander.

In the drawings. I have represented 'a diagrammatic refrigerating cycle in whlch the compressor or pump 1 pumps the hot gas through the tube 2, to the condenser 3, .where the gas is condensed and becomes a liquid, from there it passes in liquid state throu h the tube 4, ex anslon valve 5, tube 6 to the expander 7.

from which it is umped through tube 8, check valve 9, tu e 10 through the compressor to repeat the cycle. The compressor may be any well type but I have shown amultistage 'pump with two pairs of helical gears 20 and 21 of different volumetric capacity decreasing .fromlow to high. (Shown in section.) 22

is an oil. se arator in which the sealing oil sure dropping back The pipe 23 connects the high side to the from the hot'gas at high presis separate mto a oil receptacle.

oiling lantern on drive shaft.

The condenser may be anymtype, for the purpose of enplanatipng l illustrate an air cooled condenser consisting'of a plurality.

of vertical risers, ending in drums 31 and 32. i

a As these devices as wellas the check valve expansion valve are wellknown in the her detailed explanation is reand art no ,fu quired. p

In such a'cycle thewefrigerant after passto confine myself to that ap-' here the liquid boils off and becomes cold gas at low pressure,

known ing the expansion valve 5' in liquid form, begins to take' on. heat and boil and evaporates throwing 011' its gas. This gas is pumpedv out of the expander 'Z by the compressor and the evaporation is very rapid, due to the amount 'of heat being received at the tension.

'When I charge the condenser 3 with" alcohol, the alcohol passes along with the refrigerant and sludges the low side. Any moisture in the refrigerant is left in solution with the alcohol, the refrigerant boils off leaving the water. The law of frac- 'tional distillation governs the deposit of alcohol and water V as 'the refrigerant boils off.

Where provision is made for a sludge pocket inc mediately following the expansion valve, where the alcohol may lie and entrap any frost crystals carried along byT the Fefrigerant. These crystals are deliquesced by I charge the low side with alcohol,

the alcohol and non-freezing sludge formed. a

This sludge being heavier than the refrigerant will rest in all the low spots in the low side, provision being made that there shall be low spots in the lines.

Ethyl alcohol is highly miscible with water and forms with it a mixture that only solidifies' at very low temperatures but the vapor rte'nsion of ethyl alcohol is about twohund d times less than the vapor tension of water, with "these facts it is evident that ethyl chloride and alcohol mixed in proper proportion will produce an ideal refrigerant for an automatically controlled machine without recourse to special valves or fittings. for trapping out the moisture and without manual attention from time to time.

I am aware of the fact that various mechanical means have been employed from time to time to trap out the moisture from the circulating lines and to gather the frost crystals such as manual operated valves and catch basins to pocket them off from the circulating lines and especially the expansion valve so as topermit continued flow of the refrigerant but I. know of no method for reventing the formation of frost 0 s tals y the formation of an alcoholic slu gethe mixture being condensed and trapped out of the system but I do not know of any one using a mixture of alcohol and a liquid refrigerant for the pur use of forming a sludge which is pumpe through the hnes ofra refrigerating machine to clear. all frost crystals outof the lines and collectin" low side. I

the crystals and sludge iii low spots 0 the Having thus fully described my invention what I claim and desire to secure by Letters Patent is:

1. A method of preventing the formation of frost crystals in the circulating lines of a refrigerating machine which includes the step of mixing with the refrigerant a liquid highly miscible with water, providing a non-freezing sludge in the low sidecirculating the sludge through the lines and collecting it in low spots thereby preventing interference in the circulating lines.

2. A method of preventing the formation of frost crystals in the circulating lines of a refrigerating machine, which includes the step of forming an alcoholic sludge in the refrigerant, and pumping the sludge through the circulating lines and collecting it in the low side. i

3. A method of preventing the formation of frost crystals in the circulating lines of a refrigerating machine, which includes the step of mixing with the refrigerant a less volatile liquid than the refrigerant and one that is highly miscible with water, so that the refrigerant will circulate freely, boil off its gas and leave behind an unfrozen sludge, and pumping the, sludge through the circulating lines.

4. A method of preventing the freeze up of the circulating lines of a refrigerating machine which includes the step of combining with the liquid refrigerant a less volatile liquid miscible with Water so that a non-freezing sludge is formed within the circulating lines by combining with the Water found therein, and pumping the sludge through "the lines to clear it of any frost obstruction and collecting. the sludge in low spots in the lines.

In testimony whereof I aiiix my signature in the presence of two. witnesses.

HAZOR J UDSON SMITH. Witnesses:

Gmnen'rr H. Rnnse, GEO. C. S'rnBmNs. 

